zoj 1363 Chocolate

#include <iostream>#include <vector>#include <stdio.h>#include <string.h>using namespace std;#define eps 1e-8int c, n, m;void run() {        if (m > c || n < m) {     printf("0.000n");     return;}        if (n == 0) {     printf("1.000n");     return;}        vector<vector<double > > mm(2, vector<double>(c + 1, 0.0));        mm[0][1] = 1.0;        int flag = 0;        if (n > 1000) {     if (n % 2) n = 1001;     else n = 1000;}        for (int i = 1; i < n; ++i) {     flag = 1 - flag;     mm[flag].assign(c + 1, 0.0);     for (int j = 0; j <= c; ++j) {  if (j + 1 <= c) mm[flag][j + 1] += mm[1 - flag][j] * (c - j) / c;  if (j - 1 >= 0) mm[flag][j - 1] += mm[1 - flag][j] * j / c;}}        printf("%.3lfn", mm[flag][m]);}int main() {        while (scanf("%d", &c) && c) {     scanf("%d %d", &n, &m);     run();}        return 0;}